2018年7月6日玛曲局地暴雨天气过程分析

Analysis of Local Rainstorm Weather Process in Maqu on July 6,2018

2018年7月6日玛曲局地暴雨天气过程,中高纬度为两槽一脊环流形势,亚洲中低纬度受副热带高压控制,副热带高压比较强,甘南恰好处于副热带高压内部,受西南气流的影响,584 dagpm线西伸到青藏高原西部地区,青藏高原东部有低涡生成,巴湖槽东移到90°E附近时,槽后冷空气分裂南下进入低涡与低涡相结合形成北槽南涡形势,且低涡一直维持在高原东部,使河西中部到高原中部出现暴雨天气。这种形势下,过程以阵性天气开始,以非阵性天气结束,过程雨强不强,但持续时间较长。本次暴雨过程作为汛期暴雨的特殊典型,应当引起预报员的注意。

On July 6,2018,the weather process of local rainstorm in Maqu was characterized by a circulation pattern of two troughs and a ridge in the mid-high latitudes.The mid-low latitudes in Asia were controlled by the subtropical high,and the subtropical high was strong.Gannan was just inside the subtropical high and was affected by the southwestern airflow,and the 584 dagpm line extended to the western part of the Qinghai-Tibet Plateau,and a low vortex was generated in the eastern part of the Tibetan Plateau.When the Bahu trough moved east to near 90°E,the cold air behind the trough split southward into a low vortex and combined with the low vortex to form a south vortex north trough,and the low vortex had been maintained in the east of the plateau,causing heavy rain in the middle of the Hexi to the middle of the plateau.In this situation,the process started with gusty weather and ended with non-stormy weather.The rain was not strong but the duration was longer.This torrential rain process was a special model of torrential rain in flood season,and should be brought to the attention of forecasters.